INCREASED ALPHA(1B)-ADRENOCEPTOR MESSENGER-RNA LEVELS IN THE RAT-KIDNEY AFTER THYROIDECTOMY

Oligonucleotide probes were designed to sequences of the rat alpha1B- and alpha2B-adrenergic receptor mRNA and used for in situ hybridizatio n histochemistry on tissue sections of kidneys from control and thyroi dectomized rats. Both alpha1B- and alpha2B-receptor mRNA labelling was demonstrated in proximal tubule cells in the outer stripe of the oute r medulla, with tubular rays radiating into the cortex. Thyroidectomy induced a more than 4-fold increase in mRNA for the alpha1B-receptor i n the kidney, whereas no change in alpha2B-receptor mRNA levels could be demonstrated in thyroidectomized rats as compared to control animal s. The results suggest that thyroid hormone plays an important role in regulating expression of alpha1B-receptors in renal tubule cells.